Machine for vacuum-tube manufacture



later applied from Without to collapse the 'glass envelope on the stem.

After the stem has been heated to the desired temperature in position 46 the arm is moved to position 50 Where a Haine 51 is provided for applying from Without the preliminary heating to the constricted portion on the glass envelope. In this position 50 the cog wheel 52 engages cog Wheel 53 so that the glass stem andfehvelope may be rotated and the flame 51 applied uniformly to all sides of the constricted portion of the envelope. Cog Wheel 53 is shown to be connected by a beltl 54 to a mounted on a shaft 56 able means not shown. After the `preliminary heating of the envelope at position 50 the arm Ais then moved into 'position 60, where three flames 61, 62 and 63 are provided for heating the constricted portionof the glass envelope to a still higher temperature. These flames are adjusted to give a more intense and concentrated heat. Cog wheel 23 With which cog Wheel 22 engages is driven by shaft 56 so that the flamesl, 62 and 63 may be applied uniformly to alliside's of the glass envelope Where 'it is desired to have the envelope collapse to effect the sealing. The lfinal heating of the velope takes place in position 65 ,Where six still hotter flames 66 to 71 inclusive cause the constricted portion of the envelope to collapse and become sealed to the lared .out portion of the electrode supporting stem. The glass envelope may be rotated in position 65 in a manner similar to that described with reference to positions 50 and 60.

As soon as the glass envelope has been satisfactorily sealed `to the electrode supporting stem the arm may then be moved to position 45. The tube With the sealed-in stem may then be removed from its-,support. Another envelope and stem may be mounted on the arm and moved successively tofpositions 46, 50, 60 and 65 in order that they may be sealed together.

In order to` insure that the arms will be stopped cach time in the proper position with respect to the heating flames, each arm provided With'a projecting lugA 75, which :is adapted to be engaged With the stationary slotted member 76 at position 65. A foot pedal 77 is provided for suitably releasiingr the lugi from. the slot ot' member 76 whenever it is desired that the arms should be moved.

Vig. 3 is a longitudinal view showing theV .clation of the constricted portion 37 of the envelope to the flared out portion 25 of the electrode supporting stom prior to the application of heat. Fig.`4. shows hovv the Walls of lthe constrictcd portion 37 have collapsed pulley 55 whichis4 driven by any suitunderneath to eiect the sealing with the stem 25. l l 's It is to be understood that this invention is not limited to the particular forni .def supporting arm for said envelope and said electrode support, means for applying heat to said electrode support, and means for subsequently applying heat to the constricted portion of said envelope.

2. A machine for sealing al glass stem i1. a glass envelope having anIAapertured constricted portion, said machine comprising' a movable arm, a rotatable shaft on said arm, supporting means on said shaft for said stein and said envelope, said stem being surrounded bysaid envelope, means for applying heat directly to the lower portion of said stem through the opening in said constricted portion, and means for applying heat directly to said constricted-portion to cause the Walls of the constricted portion to collapse and become sealed to the heated portion of said stem.

3. A machine for sealing a glass stein in a glass envelope having an apertured constricted portion, said machine Comprising a movable arm, a rotatable rshaft on said arm, supporting means for said shaft for holding said stem in the desired relation to said'envelope, said stem being-*surrounded by said envelope, means at one position of said arm vfor applying- `heat directly to said Stein through the opening in said constricted portion, and means at another position of said arm tor applying stricted portion Kto cause the Walls thereof' to collapse and become sealed to the heated portion of said stem.

4. A machine for sealing' a glass stem in a glass envelope having an apertured constricted portion, said machine comprisingr a plurality ot movable arms, a rotatable Shaft on each of said arms, supportingr means on said shaft for holding the glass stein in the desired relation to said envelope, said stein being); surrounded by said envelope, a heatingT Haine adjacent one position said arms may have for applying` heat directly to said stein through the opening in said'constric-t-v ed portion, and a heating flame adjacent another position said arms may have for applying heat directly to said constricted portion to cause the walls thereof to collapse and hecome sealed to the-heated portion of said stem.

In witness whereof, hereunto subscribe iny naine this Oct. 8, A. D., 1919.

, Arianna BOARDMAN.

heat directly to said con- 

